1. Field of the Invention
The present invention relates to: an instruction input device to be embedded on operation panels of tablet computer terminals, image forming apparatuses, and the like, the operation panels being configured to input instructions to the tablet computer terminals and the image forming apparatuses, the operation panels being deposited on the front of display screens of displays, such as liquid crystal displays, of the tablet computer terminals and the image forming apparatuses; and a recording medium with a program stored thereon to make a computer of the instruction input device change a contact detectable area.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
In recent years, it has become very common for display, such as liquid crystal displays, to have electrostatic touch panels. With the trend toward less frame width and flatter design, electrostatic touch panels fully covered with glass, including undetectable areas thereof, have become common.
At the same time, with this growing trend, when operating such an electrostatic touch panel by touch controls, users have encountered a problem of mistouching on the touch panel because they tend to accidentally touch with their palms of hand, at a position of the margin surrounding the electrostatic touch panel, i.e., at a position close to a side of frame of the electrostatic touch panel.
Specifically, there are large-size touch panels to be loaded on liquid crystal displays for fixed machines such as multifunctional digital image forming apparatuses also referred to as MFPs, having various functions of copier, printer, facsimile, and scanner, and when operating such a touch panel, users have encountered a problem of mistouching on the touch panel more often because they tend to accidentally touch with their palms of hand, at a position close to a side of frame of such a large-size touch panel while only trying to reach keys spreading the hands with the palms down customarily.
Furthermore, some liquid crystal displays have hardware keys at a position close to touch panels, and when operating such a touch panel, users have also encountered a problem of mistouching on the touch panel because they tend to accidentally touch at a position of the margin surrounding the touch panel while only trying to reach hardware keys.
To address the problem of mistouch, Japanese Unexamined Patent Publication No. 2002-082765 discloses a technique to perform calculation by a capacitance input portion, using a maximum value and values before and after recording the maximum value at a detection point, and cancel generated coordinate data if the calculated value is less than a first threshold.
According to Japanese Unexamined Patent Publication No. 2002-082765, a conventional instruction input device simply judges whether or not a user touched on a touch panel with his/her palm of hand when detecting the contact. There is no description such that the conventional instruction input device identifies the coordinate of a contact position quickly after detecting a user's touching on the touch panel; i.e., even by applying this invention, it is not possible to achieve an instruction input device which identifies the coordinate of a contact position quickly after detecting a user's touching on a touch panel.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.